# Types of contracts At launch, our beta on Arbitrum will offer several pairs (ETHDAI, ETHUSDC, DAIUSDC) with different maturities. This will change in the future as we integrate more pairs and maturities, and eventually move to Ethereum too. Please bear in mind that when opening a short position, under the hood Contango will open a long position through an inverse contract. The latter is simply a linear contract that offers the opposite pair (e.g. DAIETH). Indeed, going long on the inverse (e.g. DAIETH) is equivalent as going short on the linear contract (e.g. ETHDAI). From a user's perspective, the only noticeable difference between longing and shorting an asset is the collateral being posted. When going short you should post the base currency (e.g. ETH) and not the quote (e.g. DAI). This is useful for instance when you have ETH and want to hedge your position by shorting it with an expirable: you can go on Contango and post it directly as collateral in a non-custodial way. #### --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://contango-2.gitbook.io/exchange/protocol/types-of-contracts.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.